The 800-metre Passetto di Borgo is a covered corridor running on top of the walls joining the Vatican to Castel Sant'Angelo, the towering cylindrical fortress on the edge of the Tiber River.

This agreement, part of an overall project for the restoration and appreciation of the Passetto, is intended to lead to the opening of this historic corridor to the public.

While confirming the interests of the Vatican and the Italian government in preserving the Passetto as a historical and cultural monument, it provides for the care of the walkway, public access, and facilities for persons with disabilities.

Erected in 1277 by Pope Nicholas III, the passageway several times served as an escape route for popes in danger.

Pope Alexander VI crossed it in 1494, when Charles VIII of France invaded the city and the pope's life was in peril.

It was used most dramatically by Pope Clement VII during the sack of Rome in 1527 by the mutinous troops of the Holy Roman Emperor Charles V.

While the Swiss Guard incurred heavy casualties in covering his retreat, Pope Clement took flight across the Passetto with little time to spare.

"Had he stayed long enough to say three creeds," wrote an eyewitness, "he would have been taken."

The Passetto played a key role in the Dan Brown novel Angels & Denons, in which four abducted cardinals are transported to the Castel Sant'Angelo, and progatonists Robert Langdon and Vittoria Vetra later use the corridor as a shortcut to the Vatican.

Sources:

Vatican Information Service

St Peters Basilica

Image: El Monillo Viajero